1. Field of The Invention
This invention relates generally to the field of high speed printing presses and, more particularly to such printing presses with dampener solution systems in which dampener solution is collected in dampener solution reservoir pans.
2. Description of the Related Art Including Information Disclosed Under 37 C.F.R Section 1.97-1.99
It is known in a high speed printing press to have separate inking and dampening trains of rollers. The inking train of rollers carry printing ink to the oleophilic and hydrophobic surface of a plate cylinder. The dampening train of rollers carry a dampener solution to the plate cylinder to selectively wash away ink from the nonprinting portions of the plate cylinder surface to form a printing image on the cylinder surface. The dampening train of rollers includes a pickup dampening roller within a dampener solution reservoir pan containing a supply of the dampener solution to remove dampener solution from the reservoir and transfer it throughout the dampening train of rollers.
A consistent distribution of dampener solution throughout the train of dampening rollers is necessary in such printing presses to maintain uniform quality of the printed product. A constant level of dampener solution throughout the reservoir is required to maintain the even distribution of the dampener solution on the pickup roller. It is known to mount a vertical standpipe in the bottom of the dampener reservoir to establish a constant dampener solution level within the reservoir. The liquid in the reservoir above the top of the standpipe drains through the standpipe opening and is removed from the reservoir. Unfortunately, in high speed printing presses the rotating inking rollers often splatter ink throughout the environs of the press. Some of this splattered ink frequently falls into the dampener solution reservoir and thereby contaminates the dampener solution. The splattered ink does not readily mix with the dampener solution; instead, it separates and floats on the surface of the dampener solution much like oil on water.
The contaminant ink on the surface of the dampener solution flows into the standpipe inlet opening and, in turn, clogs the dampener filters and pump mechanisms connected to the standpipe outlet. Disadvantageously, once the filter is clogged the level of the dampener solution rises and the printing press system must be shut down to clean or replace the expensive filters or pump mechanisms. Furthermore, a system shut down due to blockage in the dampener solution outlet lines reduces the circulation of the dampener solution in the reservoir causing the solution to stagnate. Stagnant dampener solution in a high speed printing press increases the temperature of the solution thereby changing the acidic, PH, and alkaline levels of the dampener solution. These uncontrolled changes in the chemical properties in the dampening solution adversely effect the ink viscosity at the plate cylinder decreases the quality of the printed product.
In known high speed printers, an attempt to limit the amount of contaminant ink draining into the standpipe opening has been made by means of specially shaped reservoir pans with welded baffles used to separate the accumulated ink from the dampener solution and reduce the amount of contaminant adjacent the inlet of the standpipe. Disadvantageously, even though these special baffled pans are expensive, they can only prevent a portion of the ink from draining out through the standpipe. Some of the ink on the surface migrates throughout the reservoir despite the baffles, and the baffles thereby allow a significant amount of ink to disadvantageously flow through the standpipe and into the filtering system.